Method for fabricating thin sheets of glass

ABSTRACT

Fabrication of thin sheets of glass or other substrate material for use in devices such as touch sensor panels is disclosed. A pair of thick glass sheets, typically with thicknesses of 0.5 mm or greater each, may each be patterned with thin film on a surface, sealed together to form a sandwich with the patterned surfaces facing each other and spaced apart by removable spacers, either or both thinned on their outside surfaces to thicknesses of less than 0.5 mm each, and separated into two thin glass sheets. A single thick glass sheet, typically with a thickness of 0.5 mm or greater, may be patterned, covered with a protective layer over the pattern, thinned on its outside surface to a thickness of less than 0.5 mm, and the protective layer removed. This thinness of less than 0.5 mm may be accomplished using standard LCD equipment, despite the equipment having a sheet minimum thickness requirement of 0.5 mm.

FIELD OF THE INVENTION

This relates generally to the fabrication of thin sheets of substratematerial, and more particularly, to the fabrication of thin sheets ofglass.

BACKGROUND OF THE INVENTION

The standard process for fabricating LCD panels involves, inter alia,sealing two transparent substrates together to form a sandwich fordepositing liquid crystal therebetween, thinning the sandwich to anappropriate LCD panel thickness, and depositing thin film on the outsidesurfaces of the sandwich. Conventional substrates are made from sheetsof glass or some other transparent material. In order to withstand thechemical and mechanical rigors of fabrication without deformation ordamage, a conventional sheet is generally at least 0.5 mm thick. Because0.5 mm is the thinnest dimension for the sheets being used, standard LCDfabrication equipment has been designed to have a minimum thicknesstolerance of 0.5 mm. This means that any sheet fabricated using standardLCD technology should have a thickness of at least 0.5 mm in order to behandled properly.

In recent years, touch sensor panels, touch screens, and the like havebecome available as input devices. Touch screens, in particular, arebecoming increasingly popular because of their ease and versatility ofoperation as well as their declining price. Touch screens can include atouch sensor panel, which can be a clear panel with a touch-sensitivesurface, and a display device, such as an LCD panel, that can bepositioned partially or fully behind the touch sensor panel so that thetouch-sensitive surface can cover at least a portion of the viewablearea of the display device. Touch screens can allow a user to performvarious functions by touching the touch sensor panel using a finger,stylus or other object at a location dictated by a user interface (UI)being displayed by the display device. In general, touch screens canrecognize a touch event and the position of the touch event on the touchsensor panel, and a computing system can then interpret the touch eventin accordance with the display appearing at the time of the touch event,and thereafter can perform one or more actions based on the touch event.

Like LCD panels, touch sensor panels in touch screens may be made ofglass or other suitable transparent material. However, unlike LCDpanels, touch sensor panels may be generally very thin, much more sothan LCD panels. Fabrication technology can be similar for both touchsensor panels and LCD panels. However, due to touch sensor panelthinness, difficulties can occur in fabricating them using the sameequipment as that used for LCD fabrication because the touch sensorpanels may not fit the equipment and/or may be too fragile to withstandthe rigors of the fabrication process. As such, equipment specificallydesigned for fabricating touch screen panels may be needed, which can bevery expensive.

SUMMARY OF THE INVENTION

This relates to the fabrication of thin sheets of glass or othersubstrate material for use in devices such as touch sensor panels. Insome embodiments, fabrication can be achieved using standard LCDtechnology. Standard equipment for fabrication of LCD panels has beendesigned with a minimum thickness tolerance of 0.5 mm. This is becauseglass (or other transparent material) used to fabricate LCD panelsshould be at least 0.5 mm thick in order to withstand the rigors offabrication. Thinner glass would be subject to deformation or damage.

To fabricate thin sheets of glass, a pair of thick glass sheets may beprovided, typically with thicknesses of 0.5 mm or greater each. Patternsof thin film may be deposited on a surface of each glass sheet for useas conductive traces, anti-reflective material, and/or protectivelayering, for example. The pair of thick glass sheets may be sealedtogether to form a sandwich with their patterned surfaces facing eachother and separated by removable spacers. Either or both of thesandwiched thick glass sheets may be thinned on their respective outsidesurfaces to thicknesses of less than 0.5 mm each. The sandwich of nowthin glass sheets may be separated from each other. Either or bothsheets may have thicknesses less than the minimum thickness requirementfor standard LCD equipment, yet be fabricated using that same equipment.

To fabricate thin sheets of glass, a thick glass sheet may be provided,typically with a thickness of 0.5 mm or greater. Patterns of thin filmmay be deposited on a surface of the glass sheet for use as describedpreviously. A removable protective layer may be placed over thepatterned thin film. The thick glass sheet may be thinned on its outsidesurface opposite the protective layer surface to a thickness of lessthan 0.5 mm. The protective layer may be removed. The sheet may have athickness less than the minimum thickness requirement for standard LCDequipment, yet be fabricated using that same equipment.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 a illustrates an exemplary pair of thick glass sheets patternedwith thin film on a surface according to embodiments of the invention.

FIG. 1 b illustrates an exemplary pair of thick glass sheets which aresealed together with their patterned surfaces facing each other andseparated by spacers to form a sandwich according to embodiments of theinvention.

FIG. 1 c illustrates an exemplary sandwich of patterned glass sheetswhich has been thinned on outside surfaces according to embodiments ofthe invention.

FIG. 1 d illustrates an exemplary sandwich of thin patterned glasssheets which has been coated with thin film on outside surfacesaccording to embodiments of the invention.

FIG. 1 e illustrates an exemplary pair of thin glass sheets which arecoated with thin film on one surface and patterned with thin film on theopposite surface according to embodiments of the invention.

FIG. 2 illustrates an exemplary method for fabricating a pair of thinglass sheets according to embodiments of the invention.

FIG. 3 a illustrates an exemplary thick glass sheet patterned with thinfilm on a surface according to embodiments of the invention.

FIG. 3 b illustrates an exemplary thick glass sheet patterned with thinfilm on a surface and with a protective layer of material overlaying thethin film pattern according to embodiments of the invention.

FIG. 3 c illustrates an exemplary thick glass sheet patterned with thinfilm on a surface and with a protective layer of material overlaying thethin film pattern, where the outside surfaces of the sheet and the layerhave been thinned according to embodiments of the invention.

FIG. 3 d illustrates an exemplary thin patterned glass sheet with a thinprotective layer of material thereon, where the sheet has been coatedwith thin film on the outside surface according to embodiments of theinvention.

FIG. 3 e illustrates an exemplary thin glass sheet which is coated withthin film on a surface and patterned with thin film on the oppositesurface according to embodiments of the invention.

FIG. 4 illustrates an exemplary method for fabricating a thin glasssheet according to embodiments of the invention.

FIG. 5 a illustrates an exemplary digital media player having a touchsensor panel that includes a thin glass sheet according to embodimentsof the invention.

FIG. 5 b illustrates an exemplary mobile telephone having a touch sensorpanel that includes a thin glass sheet according to embodiments of theinvention.

FIG. 6 illustrates an exemplary computing system including a touchsensor panel utilizing a thin glass sheet according to embodiments ofthe invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

In the following description of preferred embodiments, reference is madeto the accompanying drawings which form a part hereof, and in which itis shown by way of illustration specific embodiments in which theinvention may be practiced. It is to be understood that otherembodiments may be utilized and structural changes may be made withoutdeparting from the scope of the preferred embodiments of the invention.

This relates to the fabrication of thin sheets of glass or othersubstrate material for use in devices such as touch sensor panels. Insome embodiments, fabrication can be achieved using standard LCDtechnology. Standard equipment for fabrication of LCD panels has beendesigned with a minimum thickness tolerance of 0.5 mm. This is becauseglass (or other transparent material) used to fabricate LCD panelsshould be at least 0.5 mm thick in order to withstand the rigors offabrication. Thinner glass would be subject to deformation or damage.

Touch sensor panels may be significantly thinner than LCD panels, butuse similar fabrication methods. Therefore, using standard LCDtechnology to fabricate touch sensor panels may substantially save time,cost, and labor. However, to do so, the touch sensor panels should meetthe minimum thickness tolerance of LCD equipment. One way to do so maybe by forming a sandwich of two sheets such that the combined thicknessof the sandwich during fabrication does not drop below 0.5 mm. As such,each sheet in the sandwich can be thinned during fabrication to athickness of less than 0.5 mm. Another way to do so may be by applying aprotective layer to a sheet such that the combined thickness duringfabrication does not drop below 0.5 mm. As such, the sheet can bethinned during fabrication to a thickness of less than 0.5 mm. Afterthinning, the sheets can be separated, resulting in separate sheets thatare thinner than could be achieved had the sandwich not been formed.This process can result in thin glass sheets suitable for touch sensorpanels. Moreover, for the pairs of sheets, the throughput may increasesubstantially because two thin sheets may be processed at once.

Although embodiments of this invention are described and illustratedherein in terms of touch sensor panels with glass substrates, it shouldbe understood that embodiments of this invention are not so limited tosuch panels and substrates, but is generally applicable to panelsutilizing other touch and proximity sensing technologies, and anysubstrate for which thinness is required.

FIG. 1 a illustrates an exemplary pair of thick glass sheets patternedwith thin film on a surface according to embodiments of the invention.In the example of FIG. 1 a, thick glass sheet 100-a may have a thicknessof d_(1a) and thick glass sheet 100-b may gave a thickness of d_(1b).Thicknesses d_(1a) and d_(1b) may or may not be the same. Conventionalthick glass sheets may typically be 0.5 mm thick or greater.

Patterns of thin film 105-a may be deposited on a surface of glass sheet100-a. Similarly, patterns of thin film 105-b may be deposited on asurface of glass sheet 100-b. The thin film patterns may be used asconductive traces for carrying signals and may include transparentmaterials, such as indium tin oxide (ITO). Alternatively oradditionally, the thin film patterns may be used as an anti-reflectivelayer to minimize reflection off the glass sheet surface and may includeanti-reflective material. Alternatively or additionally, the thin filmpatterns may be used as a protective layer and may include ceramicmaterial or any other material with similar protective properties. Thetype of thin film used may depend on the ultimate use of the fabricatedthin glass sheet.

FIG. 1 b illustrates an exemplary pair of thick glass sheets which aresealed together with their patterned surfaces facing each other andseparated by spacers to form a sandwich according to embodiments of theinvention. In the example of FIG. 1 b, thick glass sheets 100-a and100-b of FIG. 1 a, for example, may be temporarily joined together attheir edges using any known method for doing so. For example, the edgesof glass sheets 100-a and 100-b may be laminated together using anyknown laminate. Glass sheets 100-a and 100-b may be joined together withtheir patterned surfaces facing each other. Removable spacers 110 may beplaced between the patterned surfaces to keep them apart. Spacers 110may include any material that can maintain space between glass sheets100-a and 100-b and that does not interact with the glass sheets andpatterns 105-a and 105-b. Alternatively, a removable sealant may beplaced between the patterned surfaces to keep them apart.

FIG. 1 c illustrates an exemplary sandwich of patterned glass sheetswhich have been thinned on outside surfaces according to embodiments ofthe invention. In the example of FIG. 1 c, thick glass sheets 100-a and100-b of FIG. 1 b, for example, that are sandwiched together may bethinned from respective thicknesses of d_(1a) and d_(1b) to thicknessesof d_(2a) and d_(2b), where d_(2a)<d_(1a) and d_(2b)<d_(1b). Forexample, conventional thick glass sheets having thicknesses of 0.5 mm ormore each may be thinned to thicknesses of less than 0.5 mm each. Thethinning process may include chemical etching, mechanical polishing, acombination of the two, and any other known methods for thinning glasssheets. One or both outside surfaces of the sandwich, i.e., the surfacesof glass sheets 100-a and 100-b opposite the patterned surfaces, may bethinned. Since patterns 105-a and 105-b may be sealed within thesandwich on inside surfaces, the patterns may be protected fromdeformation or damage during the thinning process. As a result of thethinning process, each glass sheet 100-a and 100-b can have a thicknessless than the minimum thickness requirement of 0.5 mm for standard LCDequipment; while the sandwich of the glass sheets maintains a thicknessat or above the requirement.

FIG. 1 d illustrates an exemplary sandwich of thin patterned glasssheets which have been coated with thin film on outside surfacesaccording to embodiments of the invention. In the example of FIG. 1 d,the thinned outside surfaces of the sandwich of thin glass sheets 100-aand 100-b of FIG. 1 c, for example, may be coated with additional thinfilm material. Thin film coating 115-a may coat the thinned surface ofglass sheet 100-a with a coating layer thickness of d_(3a). Thin filmcoating 115-b may coat the thinned surface of glass sheet 100-b with acoating layer thickness of d_(3b). The thin film material used to coatthe thinned outside surfaces of the sandwich of thin glass sheets 100-aand 100-b may be similar to the thin film material used to form patterns105-a and 105-b described above. This can provide double thinfilming—the thin film pattern on one surface and the thin film coatingon the opposite surface. This coating may be either a complete layer orjust a pattern, depending on the particular implementation for the glasssheets. Alternatively, this coating may be optional, thereby providingsingle thin filming—the thin film pattern on one surface.

FIG. 1 e illustrates an exemplary pair of thin glass sheets which arecoated with thin film on one surface and patterned with thin film on theopposite surface according to embodiments of the invention. In theexample of FIG. 1 e, the sandwich of thin glass sheets 100-a and 100-bof FIG. 1 d, for example, may be separated to form separate sheets. Thinglass sheet 100-a may have a thin film layer 115-a on one surface and athin film pattern 105-a on the opposite surface, where the glass sheetmay have a thickness of less than 0.5 mm. Similarly, thin glass sheet100-b may have a thin film layer 115-b on one surface and a thin filmpattern 105-b on the opposite surface, where the glass sheet may have athickness of less than 0.5 mm. Here, both sheets 100-a and 100-b mayhave thicknesses less than the minimum thickness requirement forstandard LCD equipment, yet have been fabricated using that sameequipment.

To separate the sandwich to form separate thin glass sheets 100-a and100-b, the sealed edges of the sheets may be cut from the sandwich andspacers 110 removed. Other mechanical methods may be used to separatethe glass sheets. Alternatively, chemical methods may be used, e.g.,delamination to remove a laminate that formed the seal. A combination ofmechanical and chemical methods may also be used.

In an example, as shown in FIGS. 1 a-1 e, two thick sheets of glass,each having a thickness of about 0.5 mm could be joined to form asandwich having a thickness of about 1.0 mm. The sandwich could bethinned to a thickness of about 0.6 mm. After the sandwich is separated,each glass sheet could have a thickness of about 0.3 mm, which would bewell below the minimum thickness requirement of standard LCD equipment.

It is to be understood that the thickness of a thin glass sheet is notlimited to that described here, but may include any thickness below theminimum thickness requirement of the LCD equipment that may be suitablefor touch sensor panels or other devices.

FIG. 2 illustrates an exemplary method for fabricating a pair of thinglass sheets according to embodiments of the invention. Optionally usingstandard LCD technology, a standard LCD thin film deposition tool may beused to place a thin film pattern on a surface of a thick glass sheet(205). The thick glass sheets may have a thickness of 0.5 mm or moreeach to meet the minimum thickness requirement of standard LCDequipment. This deposition may be repeated for multiple sheets. Astandard LCD sealing tool may be used to join a pair of the patternedthick glass sheets together to form a sandwich, with the patternedsurfaces facing each other and with removable spacers placed between thepatterned surfaces (210). The sandwich may have a thickness of 1.0 mm ormore, which also meets the minimum thickness requirement of standard LCDequipment. A standard LCD thinning tool may be used to thin one or bothoutside surfaces of the sandwich, where the thicknesses of one or bothglass sheets may each be thinned to less than 0.5 mm (215). Here, thethinned sandwich may have a thickness of 0.5 mm or more, depending onhow thin the sheets are fabricated, which still meets the minimumthickness requirement of standard LCD equipment. The standard LCD thinfilm deposition tool may be used again to coat the thinned outsidesurface of the sandwich (220) to complete the standard LCD fabricationprocess.

After completing the standard LCD fabrication process, unlike LCDpanels, the sandwich of thin glass sheets may now be separated intoseparate glass sheets. Any suitable unsealing tool known to thoseskilled in the art may be used to separate the pair of patterned thinglass sheets into separate glass sheets (225). The resulting thin glasssheet or sheets may have a thickness of less than 0.5 mm, which is belowthe minimum thickness requirement of standard LCD equipment, yet stilladvantageously have been fabricated using that equipment.

FIG. 3 a illustrates an exemplary thick glass sheet patterned with thinfilm on a surface according to embodiments of the invention. In theexample of FIG. 3 a, thick glass sheet 300 may have a thickness of d₁.Conventional thick glass sheets may typically be 0.5 mm or greater inthickness.

Patterns of thin film 305 may be deposited on a surface of glass sheet300. As mentioned previously, the thin film patterns may be used asconductive traces for carrying a signal and may include semiconductormaterials. Alternatively or additionally, the thin film patterns may beused as an anti-reflective layer to minimize reflection off the glasssheet surface and may include anti-reflective material. Alternatively oradditionally, the thin film patterns may be used as a protective layerand may include ceramic, organic, or any other materials with suchprotective properties.

FIG. 3 b illustrates an exemplary thick glass sheet patterned with thinfilm on a surface and with a protective layer of material overlaying thethin film pattern according to embodiments of the invention. In theexample of FIG. 3 b, thick glass sheet 300 of FIG. 3 a, for example, mayhave removable protective layer 310 of thickness d₂ overlaying patterns305 on the surface of the thick glass sheet. Protective layer 310 may beany material that is capable of withstanding the standard LCDfabrication equipment and that does not interact with glass sheet 300and patterns 305. The thickness of protective layer 310 may be any valuethat would ensure that the combined layer and sheet meets the minimumthickness requirement of the standard LCD equipment. For example, thethickness d₂ may be 0.5 mm or more. Protective layer 310 may protectpatterns 305 from deformation or damage during the fabrication process.

FIG. 3 c illustrates an exemplary thick glass sheet patterned with thinfilm on a surface and with a protective layer of material overlaying thethin film pattern, where the outside surfaces of the sheet and the layerhave been thinned according to embodiments of the invention. In theexample of FIG. 3 c, thick glass sheet 300 of FIG. 3 _(b), for example,may be thinned from a thickness of d₁ to a thickness of d₃, where d₃<d₁.The surface of glass sheet 300 opposite the surface having protectivelayer 310 may be thinned. For example, conventional thick glass sheetshaving thicknesses of 0.5 mm or more each may be thinned to thicknessesof less than 0.5 mm each. The thinning process may include chemicaletching, mechanical polishing, a combination of the two, and any otherknown methods for thinning glass sheets. Optionally, protective layer310 may also be thinned concurrently with glass sheet 300 from athickness of d₂ to a thickness of d₄, where d₄<d₂. Glass sheet 300 canhave a thickness less than the minimum thickness requirement of 0.5 mmfor standard LCD equipment; while the combined sheet 300 and layer 310maintains a thickness at or above the requirement.

FIG. 3 d illustrates an exemplary thin patterned glass sheet with a thinprotective layer of material thereon, where the sheet has been coatedwith thin film on the outside surface of the sheet according toembodiments of the invention. In the example of FIG. 3 d, the thinnedoutside surface of thin glass sheet 300 of FIG. 3 c, for example, may becoated with additional thin film material. Thin film coating 315 maycoat the thinned surface of glass sheet 300 with a coating layerthickness of d₅. The thin film material used to coat the thinned outsidesurface of thin glass sheet 300 may be similar to the thin film materialused to form patterns 305 described above. This may provide double thinfilming—the thin film pattern on one surface and the thin film coatingon the opposite surface. This coating may be either a complete layer orjust a pattern, depending on the particular implementation for the glasssheet. Alternatively, this coating may be optional, thereby providingsingle thin filming—the thin film pattern on one surface.

FIG. 3 e illustrates an exemplary thin glass sheet which is coated withthin film on a surface and patterned with thin film on the oppositesurface according to embodiments of the invention. In the example ofFIG. 3 e, protective layer 310 on thin glass sheet 300 of FIG. 3 d, forexample, may be removed, leaving the thin glass sheet remaining. Toremove protective layer 310 from thin glass sheet 300, any suitablechemical or mechanical method known to those skilled in the art, orcombination thereof, may be used that is capable of removing such alayer. Thin glass sheet 300 may have a thin film layer 315 on onesurface and a thin film pattern 305 on the opposite surface, where theglass sheet may have a thickness of less than 0.5 mm. Here, sheet 300may have a thickness less than the minimum thickness requirement forstandard LCD equipment, yet have been fabricated using that sameequipment.

In an example, as shown in FIGS. 3 a-3 e, a thick sheet of glass havinga thickness of about 0.5 mm could have a protective layer having asimilar thickness applied on a surface of the glass to form acombination having a thickness of about 1.0 mm. The glass sheet could bethinned so that the combination has a thickness of about 0.7 mm.Alternatively, the protective layer could concurrently be thinned sothat the combination has a thickness of about 0.6 mm. After theprotective layer is removed, the glass sheet could have a thickness ofabout 0.2 mm, which is well below the minimum thickness requirement ofstandard LCD equipment.

It is to be understood that the thickness of a thin glass sheet is notlimited to that described here, but may include any thickness below theminimum thickness requirement of the LCD equipment that may be suitablefor touch sensor panels.

FIG. 4 illustrates an exemplary method for fabricating a thin glasssheet according to embodiments of the invention. Optionally usingstandard LCD technology, a standard LCD thin film deposition tool may beused to place a thin film pattern on a surface of a thick glass sheet(405). The thick glass sheet may have a thickness of 0.5 mm or more tomeet the minimum thickness requirement of standard LCD equipment. Astandard LCD material deposition tool may be used to apply a protectivelayer overlaying the patterns on a surface of the thick glass sheet(410). The combined sheet and layer may have a thickness of more than0.5 mm, which also meets the minimum thickness requirement of standardLCD equipment. A standard LCD thinning tool may be used to thin thesurface of the glass sheet opposite the surface having the protectivelayer, where the thicknesses of the glass sheet may be thinned to lessthan 0.5 mm (415). Optionally, the protective layer may also be thinned.The combination of the thinned sheet and layer may maintain a thicknessof 0.5 mm or more, which still meets the minimum thickness requirementof standard LCD equipment. The standard LCD thin film deposition toolmay be used again to coat the thinned outside surface of the sheet (420)to complete the standard LCD fabrication process.

After completing the standard LCD fabrication process, the protectivelayer may be removed from the surface of the glass sheet. Any suitableremoval tool known to those skilled in the art may be used to do so,leaving the thin glass sheet remaining (425). The resulting thin glasssheet may have a thickness of less than 0.5 mm, which is below theminimum thickness requirement of standard LCD equipment, yet stilladvantageously have been fabricated using that equipment.

FIG. 5 a illustrates exemplary digital media player 510 that can includetouch sensor panel 515, the touch sensor panel including a thin glasssheet having a thickness of less than 0.5 mm according to embodiments ofthe invention.

FIG. 5 b illustrates exemplary mobile telephone 520 that can includetouch sensor panel 525, the touch sensor panel including a thin glasssheet having a thickness of less than 0.5 mm according to embodiments ofthe invention.

The media player and the mobile telephone of FIGS. 5 a and 5 b canachieve lighter weights utilizing thin glass sheets according toembodiments of the invention.

FIG. 6 illustrates exemplary computing system 600 that can include oneor more of the embodiments of the invention described above. Computingsystem 600 can include one or more panel processors 602 and peripherals604, and panel subsystem 606. Peripherals 604 can include, but are notlimited to, random access memory (RAM) or other types of memory orstorage, watchdog timers and the like. Panel subsystem 606 can include,but is not limited to, one or more sense channels 608, channel scanlogic 610 and driver logic 614. Channel scan logic 610 can access RAM612, autonomously read data from the sense channels and provide controlfor the sense channels. In addition, channel scan logic 610 can controldriver logic 614 to generate stimulation signals 616 at variousfrequencies and phases that can be selectively applied to drive lines oftouch sensor panel 624. In some embodiments, panel subsystem 606, panelprocessor 602 and peripherals 604 can be integrated into a singleapplication specific integrated circuit (ASIC).

Touch sensor panel 624 can include a capacitive sensing medium having aplurality of drive lines and a plurality of sense lines, although othersensing media can also be used. Either or both of the drive and senselines can be coupled to a thin glass sheet according to embodiments ofthe invention. Each intersection of drive and sense lines can representa capacitive sensing node and can be viewed as picture element (pixel)626, which can be particularly useful when touch sensor panel 624 isviewed as capturing an “image” of touch. (In other words, after panelsubsystem 606 has determined whether a touch event has been detected ateach touch sensor in the touch sensor panel, the pattern of touchsensors in the multi-touch panel at which a touch event occurred can beviewed as an “image” of touch (e.g. a pattern of fingers touching thepanel).) Each sense line of touch sensor panel 624 can drive sensechannel 608 (also referred to herein as an event detection anddemodulation circuit) in panel subsystem 606.

Computing system 600 can also include host processor 628 for receivingoutputs from panel processor 602 and performing actions based on theoutputs that can include, but are not limited to, moving an object suchas a cursor or pointer, scrolling or panning, adjusting controlsettings, opening a file or document, viewing a menu, making aselection, executing instructions, operating a peripheral device coupledto the host device, answering a telephone call, placing a telephonecall, terminating a telephone call, changing the volume or audiosettings, storing information related to telephone communications suchas addresses, frequently dialed numbers, received calls, missed calls,logging onto a computer or a computer network, permitting authorizedindividuals access to restricted areas of the computer or computernetwork, loading a user profile associated with a user's preferredarrangement of the computer desktop, permitting access to web content,launching a particular program, encrypting or decoding a message, and/orthe like. Host processor 628 can also perform additional functions thatmay not be related to panel processing, and can be coupled to programstorage 632 and display device 630 such as an LCD panel for providing aUI to a user of the device. Display device 630 together with touchsensor panel 624, when located partially or entirely under the touchsensor panel, can form touch screen 618.

Note that one or more of the functions described above can be performedby firmware stored in memory (e.g. one of the peripherals 604 in FIG. 6)and executed by panel processor 602, or stored in program storage 632and executed by host processor 628. The firmware can also be storedand/or transported within any computer-readable medium for use by or inconnection with an instruction execution system, apparatus, or device,such as a computer-based system, processor-containing system, or othersystem that can fetch the instructions from the instruction executionsystem, apparatus, or device and execute the instructions. In thecontext of this document, a “computer-readable medium” can be any mediumthat can contain or store the program for use by or in connection withthe instruction execution system, apparatus, or device. The computerreadable medium can include, but is not limited to, an electronic,magnetic, optical, electromagnetic, infrared, or semiconductor system,apparatus or device, a portable computer diskette (magnetic), a randomaccess memory (RAM) (magnetic), a read-only memory (ROM) (magnetic), anerasable programmable read-only memory (EPROM) (magnetic), a portableoptical disc such a CD, CD-R, CD-RW, DVD, DVD-R, or DVD-RW, or flashmemory such as compact flash cards, secured digital cards, USB memorydevices, memory sticks, and the like.

The firmware can also be propagated within any transport medium for useby or in connection with an instruction execution system, apparatus, ordevice, such as a computer-based system, processor-containing system, orother system that can fetch the instructions from the instructionexecution system, apparatus, or device and execute the instructions. Inthe context of this document, a “transport medium” can be any mediumthat can communicate, propagate or transport the program for use by orin connection with the instruction execution system, apparatus, ordevice. The transport readable medium can include, but is not limitedto, an electronic, magnetic, optical, electromagnetic or infrared wiredor wireless propagation medium.

Although the invention has been fully described in connection withembodiments thereof with reference to the accompanying drawings, it isto be noted that various changes and modifications will become apparentto those skilled in the art. Such changes and modifications are to beunderstood as being included within the scope of the invention asdefined by the appended claims.

What is claimed is:
 1. A method for fabricating thin sheets of glass,comprising: providing a first sheet of glass having a first thickness;providing a second sheet of glass having a second thickness; patterninga first layer of thin film on a surface of the first sheet of glass;patterning a second layer of thin film on a surface of the second sheetof glass; providing a plurality of spacers between the first and secondsheets of glass; joining the first and second sheets of glass togetherwith the patterned first and second layers of thin film facing eachother and the spacers distributed between facing surfaces of the firstand second sheets of glass along border and interior regions thereof;thinning at least one of the first and second sheets of glass on a sideopposite the patterning; and separating the first and second sheets ofglass from each other.
 2. The method of claim 1, wherein at least one ofthe first and second thicknesses is 0.5 mm or greater prior to thethinning.
 3. The method of claim 1, further comprising: forming a thirdlayer of thin film on a surface of the first sheet of glass afterthinning, the third layer formed as a complete, unpatterned layer of thesame material used in forming the patterned first or second layers. 4.The method of claim 1, wherein the joining comprises sealing the edgesof the first and second sheets of glass together.
 5. The method of claim1, wherein the thinning comprises thinning the at least one of the firstand second sheets to less than 0.5 mm.
 6. The method of claim 1, whereinthe thinning comprises at least one of chemical etching and mechanicalpolishing.
 7. The method of claim 3, further comprising: after thinning,forming a fourth layer of thin film on a surface of the second sheet ofglass the fourth layer being a complete, unpatterned layer of the samematerial used in forming the first or second layers.
 8. The method ofclaim 1, wherein the separating comprises unsealing sealed-togetheredges of the first and second sheets of glass.
 9. The method of claim 1,wherein the separating comprises removing spacers forming space betweenthe first and second sheets of glass.